Physical and chemical properties and appearance inspection of high-frequency welded steel pipes

Chemical properties of high-frequency welded steel pipes: room temperature mechanical properties, high-temperature mechanical properties, low-temperature properties, and corrosion resistance. The physical and chemical properties of high-frequency welded steel pipes mainly depend on the chemical composition of the steel, the organizational structure and purity of the steel, and the heat treatment method of high-frequency welded steel pipes.

Process performance of high-frequency welded steel pipes: flattening, flaring, curling, bending, welding, etc.

Metallurgical structure of high-frequency welded steel pipes: low-magnification structure (macro), high-magnification structure (micro) M, B, P, F, A, S

Special requirements for high-frequency welded steel pipes: contract attachments, technical agreements.

Inspection methods for high-frequency welded steel pipes:

First, chemical composition analysis: chemical analysis method, instrumental analysis method (infrared C-S instrument, direct reading spectrometer, zcP, etc.).

1. Infrared C-S instrument: analyze ferroalloys, steelmaking raw materials, and C and S elements in steel.

2. Direct reading spectrometer: C, Si, Mn, P, S, Cr, Mo, Ni, Cn, A1, W, V, Ti, B, Nb, As, Sn, Sb, Pb, Bi in block samples

3. N-0 instrument: gas content analysis N, O

Second, high-frequency welded steel pipe geometric dimensions and appearance inspection:

1. High-frequency welded steel pipe wall thickness inspection: micrometer, thickness gauge, no less than 8 points at both ends, and record.

2. High-frequency welded steel pipe outer diameter and ovality inspection: caliper, vernier caliper, ring gauge, measure large and small points.

3. High-frequency welded steel pipe length inspection: steel tape measure, manual and automatic length measurement.

4. High-frequency welded steel pipe curvature inspection: ruler, level ruler (1m), feeler gauge, and fine wire to measure curvature per meter and full-length curvature.

5. High-frequency welded steel pipe end face groove angle and blunt edge inspection: angle ruler, card plate

Third, high-frequency welded steel pipe surface inspection: 100%

1. Manual visual inspection: lighting conditions, standards, experience, marking, high-frequency welded steel pipe rotation.

2. Nondestructive testing inspection: lighting conditions, standards, experience, marking, high-frequency welded steel pipe rotation.

3. Wave flaw detection UT: It is sensitive to surface and internal crack defects of uniform materials of various materials.